1. Field of the Invention
The invention relates to a light-collimating film having excellent collimation effect and brightness performance.
2. Description of the Related Art
FIG. 1 shows a schematic diagram illustrating a conventional optical film 100 having light-collimating effect, and FIG. 2 shows an enlarged cross-section cut along line A-A′ of FIG. 1. Referring to FIG. 1, the optical film 100 includes a transparent substrate 102, a plurality of reflective elements 104, and a plurality of lenticular lenses 106. The transparent substrate 102 has a light incident surface 102a and a light-emitting surface 102b opposite the light incident surface 102a. A plurality of reflective elements 104 are formed on the light incident surface 102 and a longitudinal aperture 108 is defined on the light incident surface 102 by each two adjacent reflective elements 104. A plurality of lenticular lenses 106 are formed on the light-emitting surface 102b, and each of the lenticular lens 106 extends in a direction parallel to the longitudinal direction of the longitudinal aperture 108 to spread on the entire light-emitting surface 102b. Referring to FIG. 2, when emitting light beams of a backlight source (not shown) are incident on the optical film 100 at different angles, some incident light beam (such as S1) having a comparatively large incident angle is reflected by the reflective elements 104 and then returns to the backlight source to be recycled, and some incident light beams (such as S2 and S3) that pass through the longitudinal aperture 108 are deflected by the lenticular lenses 106 to propagate at an on-axis viewing direction (normal direction of the optical film 100).
However, though the above design enables most of the incident light beams to emit from the optical film 100 at an on-axis viewing direction, there is still much room to improve the collimation effect and brightness performance.